Flyers on a wall outside of the prayer room at the Islamic Culture Center in Newark, New Jersey. Photograph: Charles Dharapak/AP

Shortly after 9/11, the New York police department launched a massive surveillance program. Here's how it worked: the NYPD dispatched a vast network of plainclothes officers and informants – known as “rakers” and “mosque crawlers” – into Muslim neighborhoods, to eavesdrop on conversations in mosques, student associations and cafes.

In their new book Enemies Within, Pulitzer-winning journalists Matt Apuzzo and Adam Goldman detail the radical counterterrorism plan that transformed New York’s privacy and allowed the NYPD infiltrate and surveil Muslims around the city.

Their investigation, based on hundreds of previously unpublished internal memos, and exclusive interviews with intelligence sources, shows how many of the NYPD's strategies aren’t even close to being useful, functional, or successful.

Today between 2 and 3pm ET (7-8pm BST), Goldman and Apuzzo will take your questions about the strengths and weaknesses of America's counterterrorism efforts in the wake of 9/11, and reveal some of what they learned during their investigation.

We asked them a few questions to get started but post your questions in the comment thread below.

For our readers who haven’t yet read the book, describe the findings of your investigation in 6 words.

Domestic spying didn't save the day.

Did you discover any evidence that the surveillance plans actually worked?

The NYPD was uniquely prepared to unravel this plot. The Intelligence Division, with help from the CIA, built programs that used plain-clothes detectives to eavesdrop in Muslim neighborhoods, to map where Muslims work, shop, live and pray, and to document their views on subjects like the State of the Union address and the CIA's use of drones. Police informants recorded sermons inside mosques and collected license plates of everyone who prayed there. Police kept files on Muslims who changed their names to sound more American, as well as new converts to Islam who took on Arabic-sounding names.

Did anyone in the NYPD object to spying on Muslims?

Nobody could object because nobody knew about it.

Unlike other police departments, the NYPD does not tell the City Council about its operations. It does not reveal its organizational chart, its tactics or its files. The Intelligence Division has never been audited. Just as we're seeing with the NSA debate, the public was left in the dark about how extensively the government was keeping tabs on people.

What do you make of NYPD Commissioner Ray Kelly's full-throated attack on your work?

We've asked repeatedly to sit down and discuss these matters with Kelly. Even before the book came out, he dismissed it as fiction. We posted many of the NYPD's internal documents on our website http://www.enemieswithinbook.com so people can read them as they read the book and reach their own conclusions.

Are there reasons to think a new mayor will continue spying on New York-area Muslims?

It's hard to say. Domestic surveillance isn't a topic any politician wants to campaign on, not just in New York. Which is a shame because this is such an important discussion to have and people are much more ready to have it than the politicians.

Do you see any parallels in how the US government defends the NSA surveillance programs and how the NYPD defended its own?

For sure. The government response to both has been: It's all legal." And that's really beside the point. The bigger issue in all of these discussions is whether the public gives its consent, as a policy, to increasing levels of domestic surveillance. You can't give your consent to something that you don't know about. And since the City Council didn't know what was going on with NYPD Intelligence, Congress didn't know, voters didn't know, how can we be sure it's a good policy that works? Ironically the NSA has much more oversight than NYPD Intelligence, yet even some members of Congress say they were left in the dark about what NSA was doing.

Post your questions in the comment thread below. Matt and Adam will be back at 2pm to respond.

Why do you think that Muslims are a consistent target of and scapegoat for anti-terrorism, even though the majority of the community, particularly in the United States, is strongly opposed to radicalism?

There's a lot of fear, of course. We all remember the pictures of hijackers, those cold angry faces staring at us 12 years ago today. For a lot of people, Islam is a foreign concept, and the Arab and South Asian communities are not yet politically entrenched and established the way other immigrant communities have become.

Good question. People perceive the threat coming from the Muslim community. U.S. Congressman Pete King has been very vocal about saying the NYPD should be in the Muslim community because that's where the threat exists. But the number of people who have died in the U.S. since 9/11 at the hands of terrorists is very small. More people have died post-9/11 at the hands of disturbed white men -- see the mass shootings at the theater in Colorado and the school in Connecticut.

What is getting lost in our stories? The controversial Demographics Unit was one program among many. The NYPD ran many programs such as the Terrorist Interdiction Unit that handles the informants; the Special Services Unit that handles police undercovers; the Debriefing program targeted people who landed in jail, people from certain countries they could turn into informants. There was the Technical Operations Unit that conducted surveillance. There was an even something called the X-Team that would stop people and determine their IDs. We lay this out in the book.

This is a difficult topic. It's hard for a country's citizens to have an open debate about surveillance if it's secret. In the case of Snowden and the NSA, the American public is now getting the information it needs to have an informed debate about the activities of the NSA.

This comment has been chosen by Guardian staff because it contributes to the debate

Has the American Muslim community been forthcoming in reporting any radicals that may try and radicalize others in their own communities?

In this, i also include the reporting of Imams that are brought over from the other countries that may have strong anti-Western feelings, and who try to spread their ideology from within the American Muslim community.

Great question. Yes, there are many examples of Muslims who tip off law enforcement. In fact, one of the major concerns among counterterrorism officials is that too much surveillance will actually make the country less safe by damaging those important relationships.

Lots of questions! Luckily for me, they pretty much all have the same answer.

In the end, it all comes down to this. Surveillance is part of a social contract. We empower our government to do things like lock us up, search our homes, and put us under surveillance because we receive safety in exchange. Some people are willing to give more authority to the government. Some people are willing to give less. That's the debate, and it's not a new one.

But you can't have a social contract if you don't know what you've given up and you don't know what you're getting in return. So discussions like these, whether about NSA or NYPD, are important for democracy.

Last year, there were a number of polls in which New Yorkers supported the NYPD's efforts. Brad Lander, a City Council member, said he proposed legislation to create an inspector general at the NYPD because of the Muslim spying. But that largely went unnoticed as the media focused on stop and frisk which affected nearly 5 million people, most of whom were black or Hispanic. So stop and frisk dominated the conversation about police oversight. Muslim spying was an issue late in the campaign. After we published a story about the police wanting to put snitches on boards of mosques and this one Arab-American organization, Bill de Blasio said he would review the NYPD Intelligence Division. Outrage? The Muslims were outraged. That's for sure.